OBGYN - Normal and Abnormal Labor

From Iusmicm

(Difference between revisions)
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==Definitions==
==Definitions==
*Labor: regular / rhythmic contractions, cervical dilation and effacement.
*Labor: regular / rhythmic contractions, cervical dilation and effacement.
-
**Labor is considered "preterm" if it commences before 37 weeks EGA (estimated gestational age)
+
**'''Must have cervical change''' to call it labor.
 +
**Dilation: cervix develops a wider opening.
 +
**Effacement: becomes shorter.
 +
*Labor is considered '''"preterm" if it commences before 37 weeks EGA''' (estimated gestational age)
**10-12% of pregnancies include preterm labor.
**10-12% of pregnancies include preterm labor.
-
**Labor is considered "postdates" if it commences after 42 weeks EGA.
+
*Labor is considered '''"postdates" if it commences after 42 weeks EGA.'''
-
*Braxton Hicks contractions are contractions of a weak or irregular nature.
+
*'''Braxton Hicks contractions are contractions of a weak or irregular nature.'''
==Physiology of Labor==
==Physiology of Labor==
*There are many factors that play a role in the coordinated contraction of all the uterine smooth muscle for labor.
*There are many factors that play a role in the coordinated contraction of all the uterine smooth muscle for labor.
 +
 +
*Progesterone and Relaxin are key regulating factors in animals.
*Progesterone and Relaxin are key regulating factors in animals.
-
**17alpha-hydroxyprogesterone caproate
+
**'''Relaxin does not play a role in humans.'''
 +
**When 17 alpha-hydroxyprogesterone caproate is given, we see fewer preterm contractions '''so we know progesterone plays a role but we don't see it physiologically'''.
 +
**'''Progesterone levels don't drop until after the ''placenta'' is delivered.'''
 +
 
 +
 
*Gap juctions of the uterine smooth muscle are increased near term.
*Gap juctions of the uterine smooth muscle are increased near term.
**Presumably to augment myofiber-myofiber communication for a well sequenced contraction.
**Presumably to augment myofiber-myofiber communication for a well sequenced contraction.
-
*Oxytocin, surprisingly, shows '''no change in blood levels'''.
+
**Allow easy ability for electrical potential to cross.
 +
 
 +
 
 +
*Oxytocin, surprisingly, shows '''no change in blood levels''' but there are '''increased number of oxytocin receptors'''.
**Oxytocin receptors, however are elevated.
**Oxytocin receptors, however are elevated.
-
**Furthermore, there is '''elevated decidual production'''.
+
**Oxytocin does promote the influx of calcium ions (and therefore increased contractions).
 +
**There is a '''paracrine oxytocin production''' from the ''dicidual and placenta'' with subsequent increase in receptors in the myometrium.
 +
**Made in the posterior pituitary.
 +
 
 +
 
*Several prostaglandins are elevated for labor: PGE1, PGE2, PGF2alpha
*Several prostaglandins are elevated for labor: PGE1, PGE2, PGF2alpha
 +
**Makes collagenase to help '''break down collagen of the cervix to allow dilation and effacement.'''
 +
 +
*Mother becomes more sensitive to changes in Ca at term.
*Mother becomes more sensitive to changes in Ca at term.
**This is presumably because the uterine muscle is storing up more and more Ca to augment contraction.
**This is presumably because the uterine muscle is storing up more and more Ca to augment contraction.
 +
 +
*Like prostaglandins, many cytokines are elevated: IL-1, IL-6, IL-8, TNF-alpha.
*Like prostaglandins, many cytokines are elevated: IL-1, IL-6, IL-8, TNF-alpha.
 +
**Intermediate reactions in the labor pathway.
 +
**'''Infections can sometimes induce these types of cytokines and thus ''induce labor'''''.
 +
**NO is another intermediate reactor.
==Labor and Delivery Admission==
==Labor and Delivery Admission==
*The workup for a L&D admission includes:
*The workup for a L&D admission includes:
-
**H&P
+
**H&P:
-
**Fetal monitoring
+
***Fetal monitoring
-
**Leopold’s maneuver
+
***Leopold’s maneuver
-
**Vaginal exam
+
***Vaginal exam
-
***R/o (rule out) placenta previa and ROM first
+
****R/o (rule out) placenta previa and ROM first
-
***Cervical dilation / effacement / station and fetal position
+
****Cervical dilation / effacement / station and fetal position
===Fetal Monitoring===
===Fetal Monitoring===
-
*There are several technical methods for fetal monitoring.
 
*With fetal monitoring we are concerned with the baby's heart rate and the uterine pressure.
*With fetal monitoring we are concerned with the baby's heart rate and the uterine pressure.
 +
*There are several technical methods for fetal monitoring.
 +
**We can monitor externally via ultrasound and pressure transducers.
 +
**We can monitor internally (if the membranes are ruptured) by putting a pressure transducer into the uterine cavity.
 +
***A clip on the baby's scalp can mark each R wave.
-
 
+
====Fetal Monitoring - Normals====
-
*For baby's heart rate, the baseline should be around 120-160 bpm.
+
*'''For baby's heart rate, the baseline should be around 110-160 bpm.'''
*We are looking for: variability, accelerations / decelerations
*We are looking for: variability, accelerations / decelerations
-
 
+
*For uterine pressure (contractions) we are looking for: '''frequency, duration, uterine tone.'''
-
 
+
**Tone is important because the baby gets better blood flow when the uterus is resting.
-
*For uterine pressure (contractions) we are looking for: frequency, duration, uterine tone.
+
====Variability and Accelerations / Decelerations====
====Variability and Accelerations / Decelerations====
*Variability:
*Variability:
**Absent: 0-2 bpm
**Absent: 0-2 bpm
 +
***Start worrying about fetal acidosis.
 +
***Fix the environment or get the baby out.
**Minimal: 3-5 bpm
**Minimal: 3-5 bpm
-
**Moderate: 6-25 bpm
+
**'''Moderate: 6-25 bpm''' (ideal).
**Marked: saltatory, >25 bpm
**Marked: saltatory, >25 bpm
*Fetal Monitoring:
*Fetal Monitoring:
-
**Accelerations- “15 x 15”
+
**Good, classic accelerations '''go up by 15 beats per minute and last for 15 seconds'''.
-
 
+
**If the pregnancy is less than 34 weeks, "10x10" is acceptable.
-
 
+
-
*Reactive fetal heart tracing (nonstress test)
+
-
**2 accelerations in 20 minutes or less
+
-
 
+
-
 
+
-
*Contraction stress test (Oxytocin challenge test)
+
-
**3 UC’s x 40 sec in 10 mins
+
-
**Negative = no decelerations
+
-
**Positive = >50% UC’s with late decelerations
+
-
**Equivocal = intermittent or late decelerations or significant variable decelerations
+
=====Decelerations=====
=====Decelerations=====
-
*Early declerations: occur with cntx
+
*'''Early declerations: occur with cntx'''
 +
**Start and end with the contraction
**'''Non worrisome'''
**'''Non worrisome'''
-
**Head compression leads to vagal stimulation
+
**Head compression leads to vagal stimulation at the posterior fontanelle
**Recall that vagus carries parasympathetics to the heart
**Recall that vagus carries parasympathetics to the heart
-
*Late decelerations: begin at peak of cntx or after
+
*'''Late decelerations: begin at peak of cntx or after'''
-
**Fetal hypoxia is usually the culprit of late decelerations.
+
**'''Fetal hypoxia''' is usually the culprit of late decelerations.
-
*Variable: can occur at any time
+
**Occurs due to chemoreceptors in the carotid arch that sense the decreased pO2 leading to vasoconstriction and then bradycardia
-
**Variable decelerations should raise one's suspicion for cord compression
+
*'''Variable: can occur at any time'''
 +
**Variable decelerations should '''raise one's suspicion for cord compression'''
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**'''Severity of variable decelerations are a function of blood pressure and duration'''
**'''Severity of variable decelerations are a function of blood pressure and duration'''
-
====Sinusoidal====
+
====Categories of Heart Tracings====
 +
*Category 1:
 +
**Baseline rate: 110-160 bpm
 +
**Baseline FHR variability is moderate
 +
**Accelerations: present or absent
 +
**Late or variable decelerations absent
 +
*Early decelerations present or absent
 +
 
 +
 
 +
*Category 2:
 +
**Everything not in 1 or 3
 +
 
 +
 
 +
*Category 3:
 +
**Absent baseline variability ('''recall, a sign of acidosis''')
 +
**Recurrent late decelerations
 +
**Recurrent variable decelerations
 +
**Bradycardia
 +
**Sinusoidal pattern ('''a sign of fetal hypoxia with severe anemia'''; think Rh disease)
===Fetal Lie, Presentation, Attitude, and Position===
===Fetal Lie, Presentation, Attitude, and Position===
-
*Clinical: abd palpation, auscultation of fht’s, vaginal exam
+
*Clinical: abdomenal palpation, auscultation of fht’s, vaginal exam
*Studies: u/s, x-ray, MRI
*Studies: u/s, x-ray, MRI
 +
**These are done very rarely as we can determine the lie and presentation rather easily via physical examination.
====Definitions====
====Definitions====
-
*'''Lie: relation of long axis of fetus to long axis of mother'''
+
*'''Lie: relation of long axis of fetus to long axis of mother.'''
**Longitudinal
**Longitudinal
**Transverse
**Transverse
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-
*'''Presentation: part foremost in the pelvis'''
+
*'''Presentation: part of baby foremost in the pelvis'''
**Cephalic
**Cephalic
-
**Breech
+
**Breech (bottom)
**Shoulder
**Shoulder
 +
**Face
**'''Compound:'''
**'''Compound:'''
-
***Head / hand -> watch
+
***Head / hand -> watch (usually resolves itself; may apply a noxious stimuli to the hand)
-
***Head / foot-> c-section
+
***Head / foot-> c-section (will not resolve itself; requires c/s)
*Cord prolapse (funic presentation): an '''emergency'''.
*Cord prolapse (funic presentation): an '''emergency'''.
 +
**When the cord drops into the vagina.
 +
**Must move quickly to c/s.
-
*'''Attitude: folded on itself w/ flexed head'''
+
*'''Attitude: how the baby presents its head'''
-
**extension of head?
+
**Normal attitude is folded on itself w/ flexed head
-
*'''Position: relation of presenting part to maternal pelvis'''
+
*'''Position: relation of presenting part to maternal pelvis anterior aspect'''
-
**Cephalic -> occiput
+
**When the baby ''presents cephalically'', the reference point on the baby to be referenced to the anterior pubis of the mother is the '''occiput'''
-
**Face -> mentum
+
**When the baby ''presents facially'', the reference point is the '''mentum'''
-
**Breech -> sacrum
+
**When the baby ''presents as a breech'', the reference point is the '''sacrum'''
-
**Transverse -> acromion process
+
**When the baby ''presents transverse'' (shoulder), the reference point is the '''acromion process'''
====Fetal Attitude====
====Fetal Attitude====
*There are a variety of ways the fetus can present at the os; these are called attitudes:
*There are a variety of ways the fetus can present at the os; these are called attitudes:
**Full flexion (A)
**Full flexion (A)
 +
***Normal, smallest diameter.
**Military attitude (B)
**Military attitude (B)
**Brow presentation (C)
**Brow presentation (C)
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*Leopold’s Maneuver can be used to determine the attitude of the fetus.
*Leopold’s Maneuver can be used to determine the attitude of the fetus.
 +
**First maneuver: what is occupying the fundus?
 +
***Soft like a butt or hard like a head?
 +
**Second maneuver: on which side is the fetal spine?
 +
***Third maneuver: what is presenting at the pelvis?
 +
***Soft like a butt or hard like a head?
 +
**Fourth maneuver: what is the attitude, based on the flexion / extension of the head?
 +
*Can correlate with CT if there is any questions.
 +
http://www.sciencephoto.com/image/288555/350wm/M8000133-Leopold_s_Maneuver-SPL.jpg
http://www.sciencephoto.com/image/288555/350wm/M8000133-Leopold_s_Maneuver-SPL.jpg
====Vaginal Exam====
====Vaginal Exam====
-
*Nullip versus Multip
+
*We are trying to determine if the cervix is starting to dilate or efface.
 +
*We describe effacement as a percent of normal length:
 +
**Normal length of a cervix is 4cm.
 +
**So if the cervix is observed as being 2 cm effaced, we call it 50%.
-
*Station:
+
*Station: the lowest point of the fetus in reference to the ischial spines.
 +
**The stating is described as -1 (and so on, for every centimeter) it is above the ischial spines.
 +
**The station is described as +1 (and so on, for every centimeter) it is below the ischial spines.
*Position:
*Position:
 +
**Most common is cephalic.
 +
**Use the occiput as the baby reference point when describing position against the maternal anterior pubis.
 +
**'''"right" and "left" shifts describe maternal right and left'''
 +
**To determine which aspect is the occiput, recall there are ant and post fontanelles (along which to orient) and the frontal suture (to identify the anterior aspect of the baby).
*Pelvimetry:
*Pelvimetry:
-
**Diagonal Conjugate
+
**Performed at the first pre-natal visit and upon admission for L&D.
-
**Ischial Spines
+
**Describes adequacy of the pelvis for baby delivery.
 +
**Measures pelvic inlet, the midpelvis, and the pelvic outlet.
=====Pelvic Inlet=====
=====Pelvic Inlet=====
-
*Diagonal conjugate: >11.5 cm is adequate
+
*True pelvic inlet measurement is from superior pubic ramus to the sacral prominence.
-
*True obstetric conjugate = diagonal conjugate – 1.5 to 2.0 cm
+
**However, this can't be measured directly so we measure it indirectly.
 +
**True conjugate is also called the obstetric conjugate.
 +
 
 +
 
 +
*The diagonal conjugate is measured with one's third finger, along toward the thumb.
 +
*'''True obstetric conjugate = diagonal conjugate – 1.5 to 2.0 cm'''
 +
 
 +
 
 +
*'''Diagonal conjugate: >11.5 cm is adequate'''
=====Midpelvis=====
=====Midpelvis=====
 +
*Sacrum – hallow versus shallow (flat):
 +
**Hallow is concave like a bowl of soup and gives ''more room for baby moving''.
 +
 +
*Ischial spines – blunt vs. prominent
*Ischial spines – blunt vs. prominent
 +
**blunt is better; more room
 +
 +
*Pelvic sidewalls
*Pelvic sidewalls
**Parallel = OK
**Parallel = OK
**Divergent = good
**Divergent = good
**Convergent = bad
**Convergent = bad
-
*Sacrum – hallow vs. shallow (flat)
 
=====Pelvic Outlet=====
=====Pelvic Outlet=====
-
*Bituberous diameter > 6-8 cm
+
*Bituberous diameter:
-
*Pubic arch > 90 degrees
+
** > 6-8 cm is good
 +
**Measured by placing fist up against the butt.
 +
 
 +
 
 +
*Pubic arch:
 +
** > 90 degrees is good
===Stages of Labor===
===Stages of Labor===
-
*1st Stage: beginning of cervical dilation to complete dilation
+
*1st Stage: beginning of cervical dilation to complete dilation (10 cm)
*2nd Stage: complete dilation to delivery of fetus
*2nd Stage: complete dilation to delivery of fetus
-
*3rd Stage: delivery of placenta (up to 30 minutes)
+
*3rd Stage: delivery of placenta
 +
**up to 30 minutes
*4th Stage: first hour after delivery of placenta
*4th Stage: first hour after delivery of placenta
 +
**Big fluid shift, high risk of post-partum hemorrhage.
 +
**Monitoring mom for vitals
 +
**Monitoring firmness of uterus (should remain firm to inhibit hemorrhage by pressing layers of endometrium together)
-
===Cardinal Movements of Labor====*Engagement
+
===Cardinal Movements of Labor====
-
*Flexion
+
*Engagement
 +
*Flexion (of the head)
*Descent
*Descent
*Internal rotation
*Internal rotation
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*External rotation
*External rotation
*Expulsion
*Expulsion
 +
 +
 +
*If the face is anterior, it can still extend.
 +
*If ''mentum-posterior'', there can be no extension, so it cannot deliver.
===Labor Curve===
===Labor Curve===
-
Interpret chart
+
*The first phase of minimal cervical change is latent phase.
 +
**Minutes, hours, days!
 +
*Active phase
 +
**> 1 cm change / hour
 +
*Baby will move from -5cm station to 0 to +5 as it delivers.
===Prolonged / Arrested Labor===
===Prolonged / Arrested Labor===
 +
*When labor isn't moving along, consider your '''3 Ps'''
*'''P'''ower: uterine contractions
*'''P'''ower: uterine contractions
 +
**Are they strong enough?
 +
**Give oxytocin?
*'''P'''elvis: adequate?
*'''P'''elvis: adequate?
 +
**Do your pelvimetry to make sure pathway is sufficient
*'''P'''assenger: EFW, position / attitude
*'''P'''assenger: EFW, position / attitude
 +
**Is the baby too big?
 +
**Is the position wrong? (occiput posterior)
 +
**Is the attitude wrong? (military)
===Dysfunctional Labor===
===Dysfunctional Labor===
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|>20 hr
|>20 hr
|>14 hr
|>14 hr
-
|Rest, AROM, Pit
+
|Rest, AROM (augmented rupture of membranes; helps augment maternal environment for labor), Pitocin (oxytocin)
|-
|-
!Protracted dilation
!Protracted dilation
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*History
*History
**''Caedere -> caesura'': to cut; ''seco'': to cut.
**''Caedere -> caesura'': to cut; ''seco'': to cut.
-
**Francois Rousset (1581)
+
**"Cut Cut"
-
**Max Sanger (1882)- Leipzig
+
*Francois Rousset (1581)
 +
**First reported case with survival.
 +
**Questionable
 +
*Max Sanger (1882)- Leipzig
 +
**Work on the American frontier
 +
**Sewed the womb shut!  (Whoa!)
 +
**Crazy b/c the womb was considered an awful, evil thing, that shouldn't be sewn shut b/c all those bad humors would stay inside!
 +
 
 +
 
*Most common surgical procedure
*Most common surgical procedure
-
**1965 <5%, 1996 - 20.7%, 2004 - 29.1%
+
**1965: <5%, 1996: 20.7%, 2004: 29.1%
-
**No change in cerebral palsy rate
+
*No change in cerebral palsy rate
====C-section - Techniques====
====C-section - Techniques====
-
*Uterine Incisions:
+
*Uterine Incisions
-
**Low transverse
+
*Low transverse
-
**Low verticle
+
**The most common way because it runs with the grain of the muscular fibers.
-
**Classical
+
**Also, this area does less labor contracting so next pregnancy is less likely to result in rupture.
-
**Kerr
+
*Low verticle
 +
*Classical
 +
*Kerr
====C-section - Indications====
====C-section - Indications====
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=====Fetal C-section Indications=====
=====Fetal C-section Indications=====
*Distress / intolerance of labor
*Distress / intolerance of labor
 +
**'''FHT of category 2 or 3'''
*Malpresentation (breech, transverse)
*Malpresentation (breech, transverse)
*Twins, multiples
*Twins, multiples
-
**Vtx / Vtx = allow to labor
+
**'''Vertex / Vertex = allow to labor'''
*Some congenital anomalies
*Some congenital anomalies
**NTD
**NTD
=====Maternal-Fetal C-section Indications=====
=====Maternal-Fetal C-section Indications=====
-
*Arrest of active labor
+
*'''Arrest of active labor'''
 +
**Pretty common
*Failed induction of labor (?)
*Failed induction of labor (?)
-
*Placenta previa, vasa previa
+
*'''Placenta previa, vasa previa'''
 +
**When the placenta covers the cervical os.
 +
**When the placental vessels course between baby and os.
 +
***50% mortality post-rupture!
*Active HSV outbreak
*Active HSV outbreak
*HIV+ (viral load >1000/ml)
*HIV+ (viral load >1000/ml)
-
*EFW > 4500 - 5000 gms (increasing risk of shoulder dystocia)
+
**If mom is on ARV therapy, there is no decrease in transmission with c/s.
 +
*EFW > 4500 - '''5000 grams''' (increasing risk of shoulder dystocia)
 +
**Use u/s to estimate weight.
=====Maternal C-section Indications=====
=====Maternal C-section Indications=====
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*Cervical cancer
*Cervical cancer
*Abdominal cerclage
*Abdominal cerclage
-
*Prior c-section
+
*'''Prior c-section'''
 +
**Risk of uterine rupture is 0.5-1%
 +
**Can be catastrophic
*Prior vaginal colporrhaphy
*Prior vaginal colporrhaphy
*Vaginal delivery contraindicated medically
*Vaginal delivery contraindicated medically
*Pregnant???
*Pregnant???
 +
**No!
====C-section - Risks====
====C-section - Risks====
*At time of surgery / Immediate post-op
*At time of surgery / Immediate post-op
-
*Infection: endometritis, wound infection, septic pelvic thrombophlebitis (SPT)
+
*'''Infection: endometritis, wound infection, septic pelvic thrombophlebitis (SPT)'''
*Bleeding: transfusion, hysterectomy
*Bleeding: transfusion, hysterectomy
*Damage to fetus
*Damage to fetus
 +
**Very small; no larger than with vaginal delivery.
*Damage to adjacent organs
*Damage to adjacent organs
-
*Subsequent pregnancy
+
 
 +
 
 +
*Subsequent pregnancy:
 +
**Adhesions
**Uterine rupture
**Uterine rupture
-
**Placenta previa -> accreta
+
**Placenta previa (when the placenta covers the os) may convert to accreta (when the placenta invades the myometrium).
-
***0 –> 5%
+
**Accreta carries huge risks because there is often massive bleeding.
 +
**Accreta puts the mother a risk of death.
 +
**'''That is, placenta previa with a previous c/s has a very high risk of being bad!'''
 +
***0 –> 5% (number of previous c/s, risk of accreta given a placenta previa)
***1 –> 24%
***1 –> 24%
***2 –> 48%
***2 –> 48%
***3 –> 67%
***3 –> 67%
-
**Adhesions
+
There will be a test question on prior c/s and placenta previa.
 +
 
===Operative Vaginal Delivery===
===Operative Vaginal Delivery===
-
*Forceps and vacuum
+
*Forceps and vacuum can be used to guide the baby's head out of the pelvis.
 +
*There are many different types and procedures.
====Operative Vaginal Delivery - Classification====
====Operative Vaginal Delivery - Classification====
 +
*We want, first, to be sure the baby has reached the pelvic inlet.
 +
 +
*Didn't talk about any of this:
*Outlet: scalp visible at introitus w/out separating labia; no rotation
*Outlet: scalp visible at introitus w/out separating labia; no rotation
*Low: leading point of skull at or below +2 cm station
*Low: leading point of skull at or below +2 cm station
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*Fetal skull engaged in pelvis
*Fetal skull engaged in pelvis
*Empty bladder
*Empty bladder
-
*Position! Position! Position!
+
*'''Position! Position! Position!'''
 +
**Before we put anything on the baby's head, we have to know the position so we don't break the nasal bone or deform the child.
*Adequate pelvis
*Adequate pelvis
*Adequate anesthesia
*Adequate anesthesia
====Operative Vaginal Delivery - Forceps Assisted====
====Operative Vaginal Delivery - Forceps Assisted====
 +
*Use the same angles when applying traction.
 +
*Apply the extension just like in a non-operative vaginal delivery.
====Operative Vaginal Delivery - Risks====
====Operative Vaginal Delivery - Risks====
*Maternal:
*Maternal:
**Vaginal / perineal trauma, damage to rectal sphincter
**Vaginal / perineal trauma, damage to rectal sphincter
 +
**Mostly forceps issues with mom
*Fetal:
*Fetal:
 +
**Mostly vacuum issues with baby
**Cephalohematoma
**Cephalohematoma
**Subgaleal hemorrhage
**Subgaleal hemorrhage
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**Intraventricular hemorrhage
**Intraventricular hemorrhage
-
===Birth Trauma===
+
====Birth Trauma====
*Caput succedaneum:
*Caput succedaneum:
**Very common
**Very common
**Crosses midline
**Crosses midline
*Subgaleal hemorrhage:
*Subgaleal hemorrhage:
 +
**Does not cross midline
**Rare
**Rare
**Hypovolemia and DIC
**Hypovolemia and DIC
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*PP Hemorrhage: >500cc (>1000cc for c/s):
*PP Hemorrhage: >500cc (>1000cc for c/s):
**Atony
**Atony
 +
***When the uterus won't contract.
 +
***Linings aren't collapsed together to stop bleeding.
**Lacerations (cervix, vagina, perineum)
**Lacerations (cervix, vagina, perineum)
**Retained placenta
**Retained placenta
 +
***Keeps the endometrium layers from coapting (collapsing together).
**Uterine rupture
**Uterine rupture
**Uterine inversion
**Uterine inversion
**Amniotic fluid embolism
**Amniotic fluid embolism
 +
 +
*Endometritis:
*Endometritis:
**Fundal tenderness w/ temperature >38°C x 2 or >38.5°C
**Fundal tenderness w/ temperature >38°C x 2 or >38.5°C
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***Prolonged ruptured membranes
***Prolonged ruptured membranes
***Chorioamnionitis
***Chorioamnionitis
 +
**'''Treat with broad spectrum antibiotics'''
====PP / Post-Op Fever====
====PP / Post-Op Fever====

Revision as of 22:14, 14 December 2011

Contents

Labor: Normal, Abnormal, and Points Between

Definitions

  • Labor: regular / rhythmic contractions, cervical dilation and effacement.
    • Must have cervical change to call it labor.
    • Dilation: cervix develops a wider opening.
    • Effacement: becomes shorter.
  • Labor is considered "preterm" if it commences before 37 weeks EGA (estimated gestational age)
    • 10-12% of pregnancies include preterm labor.
  • Labor is considered "postdates" if it commences after 42 weeks EGA.
  • Braxton Hicks contractions are contractions of a weak or irregular nature.

Physiology of Labor

  • There are many factors that play a role in the coordinated contraction of all the uterine smooth muscle for labor.


  • Progesterone and Relaxin are key regulating factors in animals.
    • Relaxin does not play a role in humans.
    • When 17 alpha-hydroxyprogesterone caproate is given, we see fewer preterm contractions so we know progesterone plays a role but we don't see it physiologically.
    • Progesterone levels don't drop until after the placenta is delivered.


  • Gap juctions of the uterine smooth muscle are increased near term.
    • Presumably to augment myofiber-myofiber communication for a well sequenced contraction.
    • Allow easy ability for electrical potential to cross.


  • Oxytocin, surprisingly, shows no change in blood levels but there are increased number of oxytocin receptors.
    • Oxytocin receptors, however are elevated.
    • Oxytocin does promote the influx of calcium ions (and therefore increased contractions).
    • There is a paracrine oxytocin production from the dicidual and placenta with subsequent increase in receptors in the myometrium.
    • Made in the posterior pituitary.


  • Several prostaglandins are elevated for labor: PGE1, PGE2, PGF2alpha
    • Makes collagenase to help break down collagen of the cervix to allow dilation and effacement.


  • Mother becomes more sensitive to changes in Ca at term.
    • This is presumably because the uterine muscle is storing up more and more Ca to augment contraction.


  • Like prostaglandins, many cytokines are elevated: IL-1, IL-6, IL-8, TNF-alpha.
    • Intermediate reactions in the labor pathway.
    • Infections can sometimes induce these types of cytokines and thus induce labor.
    • NO is another intermediate reactor.

Labor and Delivery Admission

  • The workup for a L&D admission includes:
    • H&P:
      • Fetal monitoring
      • Leopold’s maneuver
      • Vaginal exam
        • R/o (rule out) placenta previa and ROM first
        • Cervical dilation / effacement / station and fetal position

Fetal Monitoring

  • With fetal monitoring we are concerned with the baby's heart rate and the uterine pressure.
  • There are several technical methods for fetal monitoring.
    • We can monitor externally via ultrasound and pressure transducers.
    • We can monitor internally (if the membranes are ruptured) by putting a pressure transducer into the uterine cavity.
      • A clip on the baby's scalp can mark each R wave.

Fetal Monitoring - Normals

  • For baby's heart rate, the baseline should be around 110-160 bpm.
  • We are looking for: variability, accelerations / decelerations
  • For uterine pressure (contractions) we are looking for: frequency, duration, uterine tone.
    • Tone is important because the baby gets better blood flow when the uterus is resting.

Variability and Accelerations / Decelerations

  • Variability:
    • Absent: 0-2 bpm
      • Start worrying about fetal acidosis.
      • Fix the environment or get the baby out.
    • Minimal: 3-5 bpm
    • Moderate: 6-25 bpm (ideal).
    • Marked: saltatory, >25 bpm


  • Fetal Monitoring:
    • Good, classic accelerations go up by 15 beats per minute and last for 15 seconds.
    • If the pregnancy is less than 34 weeks, "10x10" is acceptable.
Decelerations
  • Early declerations: occur with cntx
    • Start and end with the contraction
    • Non worrisome
    • Head compression leads to vagal stimulation at the posterior fontanelle
    • Recall that vagus carries parasympathetics to the heart
  • Late decelerations: begin at peak of cntx or after
    • Fetal hypoxia is usually the culprit of late decelerations.
    • Occurs due to chemoreceptors in the carotid arch that sense the decreased pO2 leading to vasoconstriction and then bradycardia
  • Variable: can occur at any time
    • Variable decelerations should raise one's suspicion for cord compression


  • Variable Decelerations: mild, moderate, and severe.
    • Lower the blood pressure the more severe.
    • Longer the duration the more severe.
    • Severity of variable decelerations are a function of blood pressure and duration

Categories of Heart Tracings

  • Category 1:
    • Baseline rate: 110-160 bpm
    • Baseline FHR variability is moderate
    • Accelerations: present or absent
    • Late or variable decelerations absent
  • Early decelerations present or absent


  • Category 2:
    • Everything not in 1 or 3


  • Category 3:
    • Absent baseline variability (recall, a sign of acidosis)
    • Recurrent late decelerations
    • Recurrent variable decelerations
    • Bradycardia
    • Sinusoidal pattern (a sign of fetal hypoxia with severe anemia; think Rh disease)

Fetal Lie, Presentation, Attitude, and Position

  • Clinical: abdomenal palpation, auscultation of fht’s, vaginal exam
  • Studies: u/s, x-ray, MRI
    • These are done very rarely as we can determine the lie and presentation rather easily via physical examination.

Definitions

  • Lie: relation of long axis of fetus to long axis of mother.
    • Longitudinal
    • Transverse
    • Oblique


  • Presentation: part of baby foremost in the pelvis
    • Cephalic
    • Breech (bottom)
    • Shoulder
    • Face
    • Compound:
      • Head / hand -> watch (usually resolves itself; may apply a noxious stimuli to the hand)
      • Head / foot-> c-section (will not resolve itself; requires c/s)
  • Cord prolapse (funic presentation): an emergency.
    • When the cord drops into the vagina.
    • Must move quickly to c/s.


  • Attitude: how the baby presents its head
    • Normal attitude is folded on itself w/ flexed head


  • Position: relation of presenting part to maternal pelvis anterior aspect
    • When the baby presents cephalically, the reference point on the baby to be referenced to the anterior pubis of the mother is the occiput
    • When the baby presents facially, the reference point is the mentum
    • When the baby presents as a breech, the reference point is the sacrum
    • When the baby presents transverse (shoulder), the reference point is the acromion process

Fetal Attitude

  • There are a variety of ways the fetus can present at the os; these are called attitudes:
    • Full flexion (A)
      • Normal, smallest diameter.
    • Military attitude (B)
    • Brow presentation (C)
    • Face presentation (D)

001f.gif


  • Leopold’s Maneuver can be used to determine the attitude of the fetus.
    • First maneuver: what is occupying the fundus?
      • Soft like a butt or hard like a head?
    • Second maneuver: on which side is the fetal spine?
      • Third maneuver: what is presenting at the pelvis?
      • Soft like a butt or hard like a head?
    • Fourth maneuver: what is the attitude, based on the flexion / extension of the head?
  • Can correlate with CT if there is any questions.

M8000133-Leopold_s_Maneuver-SPL.jpg

Vaginal Exam

  • We are trying to determine if the cervix is starting to dilate or efface.
  • We describe effacement as a percent of normal length:
    • Normal length of a cervix is 4cm.
    • So if the cervix is observed as being 2 cm effaced, we call it 50%.


  • Station: the lowest point of the fetus in reference to the ischial spines.
    • The stating is described as -1 (and so on, for every centimeter) it is above the ischial spines.
    • The station is described as +1 (and so on, for every centimeter) it is below the ischial spines.


  • Position:
    • Most common is cephalic.
    • Use the occiput as the baby reference point when describing position against the maternal anterior pubis.
    • "right" and "left" shifts describe maternal right and left
    • To determine which aspect is the occiput, recall there are ant and post fontanelles (along which to orient) and the frontal suture (to identify the anterior aspect of the baby).


  • Pelvimetry:
    • Performed at the first pre-natal visit and upon admission for L&D.
    • Describes adequacy of the pelvis for baby delivery.
    • Measures pelvic inlet, the midpelvis, and the pelvic outlet.
Pelvic Inlet
  • True pelvic inlet measurement is from superior pubic ramus to the sacral prominence.
    • However, this can't be measured directly so we measure it indirectly.
    • True conjugate is also called the obstetric conjugate.


  • The diagonal conjugate is measured with one's third finger, along toward the thumb.
  • True obstetric conjugate = diagonal conjugate – 1.5 to 2.0 cm


  • Diagonal conjugate: >11.5 cm is adequate
Midpelvis
  • Sacrum – hallow versus shallow (flat):
    • Hallow is concave like a bowl of soup and gives more room for baby moving.


  • Ischial spines – blunt vs. prominent
    • blunt is better; more room


  • Pelvic sidewalls
    • Parallel = OK
    • Divergent = good
    • Convergent = bad
Pelvic Outlet
  • Bituberous diameter:
    • > 6-8 cm is good
    • Measured by placing fist up against the butt.


  • Pubic arch:
    • > 90 degrees is good

Stages of Labor

  • 1st Stage: beginning of cervical dilation to complete dilation (10 cm)
  • 2nd Stage: complete dilation to delivery of fetus
  • 3rd Stage: delivery of placenta
    • up to 30 minutes
  • 4th Stage: first hour after delivery of placenta
    • Big fluid shift, high risk of post-partum hemorrhage.
    • Monitoring mom for vitals
    • Monitoring firmness of uterus (should remain firm to inhibit hemorrhage by pressing layers of endometrium together)

Cardinal Movements of Labor=

  • Engagement
  • Flexion (of the head)
  • Descent
  • Internal rotation
  • Extension
  • External rotation
  • Expulsion


  • If the face is anterior, it can still extend.
  • If mentum-posterior, there can be no extension, so it cannot deliver.

Labor Curve

  • The first phase of minimal cervical change is latent phase.
    • Minutes, hours, days!
  • Active phase
    • > 1 cm change / hour
  • Baby will move from -5cm station to 0 to +5 as it delivers.

Prolonged / Arrested Labor

  • When labor isn't moving along, consider your 3 Ps
  • Power: uterine contractions
    • Are they strong enough?
    • Give oxytocin?
  • Pelvis: adequate?
    • Do your pelvimetry to make sure pathway is sufficient
  • Passenger: EFW, position / attitude
    • Is the baby too big?
    • Is the position wrong? (occiput posterior)
    • Is the attitude wrong? (military)

Dysfunctional Labor

Pattern Nullip Multip Rx
Prolonged latent phase >20 hr >14 hr Rest, AROM (augmented rupture of membranes; helps augment maternal environment for labor), Pitocin (oxytocin)
Protracted dilation <1.2 cm/hr <1.5 cm/hr AROM, Pit
Protracted descent <1 cm/hr <2 cm/hr Pit Arrest of dilation >2 hr >2 hr AROM, Pit, C/S
Arrest of descent >2 hr >1 hr Vacuum, forceps, C/S

Cesarean Section

  • History
    • Caedere -> caesura: to cut; seco: to cut.
    • "Cut Cut"
  • Francois Rousset (1581)
    • First reported case with survival.
    • Questionable
  • Max Sanger (1882)- Leipzig
    • Work on the American frontier
    • Sewed the womb shut! (Whoa!)
    • Crazy b/c the womb was considered an awful, evil thing, that shouldn't be sewn shut b/c all those bad humors would stay inside!


  • Most common surgical procedure
    • 1965: <5%, 1996: 20.7%, 2004: 29.1%
  • No change in cerebral palsy rate

C-section - Techniques

  • Uterine Incisions
  • Low transverse
    • The most common way because it runs with the grain of the muscular fibers.
    • Also, this area does less labor contracting so next pregnancy is less likely to result in rupture.
  • Low verticle
  • Classical
  • Kerr

C-section - Indications

Fetal C-section Indications
  • Distress / intolerance of labor
    • FHT of category 2 or 3
  • Malpresentation (breech, transverse)
  • Twins, multiples
    • Vertex / Vertex = allow to labor
  • Some congenital anomalies
    • NTD
Maternal-Fetal C-section Indications
  • Arrest of active labor
    • Pretty common
  • Failed induction of labor (?)
  • Placenta previa, vasa previa
    • When the placenta covers the cervical os.
    • When the placental vessels course between baby and os.
      • 50% mortality post-rupture!
  • Active HSV outbreak
  • HIV+ (viral load >1000/ml)
    • If mom is on ARV therapy, there is no decrease in transmission with c/s.
  • EFW > 4500 - 5000 grams (increasing risk of shoulder dystocia)
    • Use u/s to estimate weight.
Maternal C-section Indications
  • Obstructive tumors (some leiomyomas)
  • Severe condylomata acuminata
  • Cervical cancer
  • Abdominal cerclage
  • Prior c-section
    • Risk of uterine rupture is 0.5-1%
    • Can be catastrophic
  • Prior vaginal colporrhaphy
  • Vaginal delivery contraindicated medically
  • Pregnant???
    • No!

C-section - Risks

  • At time of surgery / Immediate post-op
  • Infection: endometritis, wound infection, septic pelvic thrombophlebitis (SPT)
  • Bleeding: transfusion, hysterectomy
  • Damage to fetus
    • Very small; no larger than with vaginal delivery.
  • Damage to adjacent organs


  • Subsequent pregnancy:
    • Adhesions
    • Uterine rupture
    • Placenta previa (when the placenta covers the os) may convert to accreta (when the placenta invades the myometrium).
    • Accreta carries huge risks because there is often massive bleeding.
    • Accreta puts the mother a risk of death.
    • That is, placenta previa with a previous c/s has a very high risk of being bad!
      • 0 –> 5% (number of previous c/s, risk of accreta given a placenta previa)
      • 1 –> 24%
      • 2 –> 48%
      • 3 –> 67% 
There will be a test question on prior c/s and placenta previa.


Operative Vaginal Delivery

  • Forceps and vacuum can be used to guide the baby's head out of the pelvis.
  • There are many different types and procedures.

Operative Vaginal Delivery - Classification

  • We want, first, to be sure the baby has reached the pelvic inlet.
  • Didn't talk about any of this:
  • Outlet: scalp visible at introitus w/out separating labia; no rotation
  • Low: leading point of skull at or below +2 cm station
    • Rotate < 45°
    • Rotate > 45°
  • Mid: above +2 cm station but engaged

Operative Vaginal Delivery - Indications

  • Nonreassuring FHT’s
  • Prolonged 2nd stage of labor
  • Shortened 2nd stage if pushing / Valsalva not indicated
  • Maternal exhaustion

Operative Vaginal Delivery - Prerequisites

  • Cervix completely dilated
  • Ruptured membranes
  • Fetal skull engaged in pelvis
  • Empty bladder
  • Position! Position! Position!
    • Before we put anything on the baby's head, we have to know the position so we don't break the nasal bone or deform the child.
  • Adequate pelvis
  • Adequate anesthesia

Operative Vaginal Delivery - Forceps Assisted

  • Use the same angles when applying traction.
  • Apply the extension just like in a non-operative vaginal delivery.

Operative Vaginal Delivery - Risks

  • Maternal:
    • Vaginal / perineal trauma, damage to rectal sphincter
    • Mostly forceps issues with mom
  • Fetal:
    • Mostly vacuum issues with baby
    • Cephalohematoma
    • Subgaleal hemorrhage
    • Bony facial trauma
    • Facial nerve injury
    • Intraventricular hemorrhage

Birth Trauma

  • Caput succedaneum:
    • Very common
    • Crosses midline
  • Subgaleal hemorrhage:
    • Does not cross midline
    • Rare
    • Hypovolemia and DIC

Common Post Partum Problems

  • PP Hemorrhage: >500cc (>1000cc for c/s):
    • Atony
      • When the uterus won't contract.
      • Linings aren't collapsed together to stop bleeding.
    • Lacerations (cervix, vagina, perineum)
    • Retained placenta
      • Keeps the endometrium layers from coapting (collapsing together).
    • Uterine rupture
    • Uterine inversion
    • Amniotic fluid embolism


  • Endometritis:
    • Fundal tenderness w/ temperature >38°C x 2 or >38.5°C
    • Polymicrobial infection
    • More common after c/s
      • Prolonged ruptured membranes
      • Chorioamnionitis
    • Treat with broad spectrum antibiotics

PP / Post-Op Fever

  • Causes and symptoms
    • Wind (atelectasis, pneumonia)
    • Wound (seroma, necrotizing fasciitis)
    • Water (UTI)
    • Walk (thrmobophlebitis)
    • Wonder drug (drug reaction)
    • Womb (endometriosis)
    • Wean (mastitis, engorgement)
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